The company, Tri-electronics Incorporated pioneered the now popular electronic gold testers used throughout the world. The Company held the basic parent patent, DYNAMIC PRECIOUS METAL ASSAY METHOD, U.S. Pat. No. 4,799,999 of Jan. 24, 1989 which was a novel method which utilized the complex chemistry of time dependant electrochemistry to determine the gold content of an alloy specimen sample in units of karats. The ongoing research, guided by worldwide customer feedback has resulted in the decision to go to insertable disposable cartridges as a unique approach to improve the basic patent, U.S. Pat. No. 4,799,999. Their newest cartridge style electronic gold tester is the subject of Published Application US-2013-0220807-A1 of Aug. 29, 2013; DYNAMIC PRECIOUS METAL ASSAY DEVICE
An excellent review of current electronic gold testers has been videotaped as a youtube™ internet presentation Gold Testers Review—Find the best gold tester for you by igemcorp Dec. 5, 2012 http://www.youtube.com/watch?v=1kd0xIdwg3U and clearly designates Tri-electronics products as the best professional gold tester on the market that uniquely uses disposable cartridge inserts of environmentally and personal safe reagents. Published Application US-2013-0220807-A1 of Aug. 29, 2013; DYNAMIC PRECIOUS MEAL ASSAY DEVICE, incorporated by reference, details the objectives of the Company R&D program of improvement of product and states these research objectives as being—                A precision and controlled feed of the electrolyte solution was needed to avoid costly waste and staining. This is now accomplished by two systems:        a) a threaded shaft which drives a piston in a cartridge;        b) an accordion springing cartridge that is pinched; where either cartridge is engaged by a rotating screw on the closure cap. The screw pitch of is designed to meter out the exact amount of electrolyte to the galvanic cell.        The electrolyte is contained in a sealed disposable cartridge, so no electrolyte is ever handled in bulk. This avoids contamination and costly spills of a toxic material as well as waste disposal control.        The body of the gold tester is a rugged casing which holds the disposable cartridge in a locked position and also has a removable porous cap tip. The casing encloses a wire feed channel for the reference electrode wire that goes to the tip where the reference electrode wire is circumferentially wrapped into the reference electrode in the removable porous cap which comprises the galvanic cell.        A removable porous cap is attached to the bottom of the casing. This porous cap is capable of holding electrolyte by surface tension and capillary action in and on its porous surface. The perforated mesh or pattern on the bottom of the cap is to be positioned against the test specimen. This system assures uniformity of specimen contact of a repeatable wetted contact with the specimen electrode as well as tight control of the geometry of the galvanic cell.        
The insertable accordion springing cartridge that was being laboratory tested was collapsed by a screw driven piston was further developed for various reasons and experienced major changes that constitutes new matter in the within application. The overall design of this novel improvement to meet the above objectives is so comprehensive as to require a new application as an improvement on the parent U.S. Pat. No. 4,799,999 of Jan. 24, 1989. The modification of the electronic pencil system now uses a resilient casing closure top which limits the stroke of the inserted pipette cartridge thereby insuring an accurate expulsion of electrolyte through a slit diaphragm at the bottom of the cartridge. The spring-like restoring action of the cartridge and top permits volumetric replacement of expelled electrolyte and also assures any extraneous electrolyte clinging to the effluent exit is reduxed into the cartridge which contributes to a self-cleaning action as well as conservation of the electrolyte. Moreover, the resilient casing top closure cap is easily removed making the insertable cartridge much more accessible for replacement. The new pencil is also much easier to manufacture making the product more competitive with the lower quality electronic gold testers on the market, but still holding to the high quality and dependability that Tri-electronics Corp has earned.